Heating apparatus



Aug. z2, 195o Patented Aug. 22, 1950 HEATING APPARATUS Charles H.Watkins, Brookfield, Ill., assignor to Universal `Oil Products Company,rChicago, Ill.

a corporation of Delaware Application June 15, 1946, Serial No. 676,914

(lCl. 263-410) l6 Claims.

This invention relates to an improved furnace design and construction,wherein is provided definitely positioned zones of greater heatintensities. More specically, the improved heater or furnace is onehaving a combustion chamber ellipsoidal in shape, with burners or heatgenerating means being positioned at the geometrical foci of theellipsoidal chamber.

It is well known that heat rays or light rays emitted from one focuspoint of an ellipsoid will be reflected directly to the other focusregardless of the direction of its travel from the original focus.Therefore, a furnace of this improved design takes advantage of thisprinciple and the heat from one flame or heat source is reflected to theopposing flame or heat source and thereby produces a very high nametemperature or highly heated zone. Furnaces or heaters of this type areparticularly desirable for various industrial or laboratory conversionprocesses requiring controlled conditions of oxidation or combustion.

The amount of reflected heat, which will govern the temperature increaseor build-up at each of the opposing foci and the heat generating means,will of course depend on the internal surface of the ellipsoidalcombustion chamber, as well as the accuracy attained in providing a trueellipsoidal shape. The reflecting power of the material is thecomplement of its adsorbing or radiating power, that is, when a body isstruck by a ray of heat, it adsorbs part of the heat and reflects therest. Thus, in a preferred con-struction of the furnace, the surface onthe interior of the combustion chamber will be Very smooth andmirrorlike in nature. However, such a high degree of smoothness andreflectivity would be impossible or impractical in large industrialheaters, or in extremely high temperature furnaces. The type of materialwhich may be used for the internal surface of the combustion chamberwill determine the amount of reflectivity and therefore the amount oftemperature increase at each of the focus points, where the heat sourcesare located. Various metals, even though polished, will have varyingheat reflectivity and adsorptivity characteristics; this also is truefor various refractory materials which are commonly used in hightemperature furnaces. For low temperature conditions of only a fewhundred degrees F., polished metals or heat resisting alloys, or metalplating, such as chrome plate and the like, will be found very efficientand desirable. For intermediate temperatures, materials such asprocelain, and insulating cement, may be used, which are relativelydense and smooth and light in color.

While for high temperature service, of say 1200 F. and upward, thecommonly used refractory oxides and like types of material may beemployed with particular effort being made to provide a smooth interiorto the inside of the combustion chamber.

It is a principal object of this invention to provide a furnace havingdefinitely positioned zones of high temperature concentration.

It is also an object of this invention to provide a furnace having hightemperature zones wherein reactant materials may be subjected tocombustion or oxidation for extremely short periods of time.

A still further object of the invention, is to provide a furnace whichis particularly adapted for operation under superatmospheric pressureconditions.

The ellipsoidal shaped furnace, such as the one comprising thisinvention, is of particular advantage for various oxidation andcombustion reactions where high temperature and short contact time isnecessary to the conversion process. For example, certain hydrocarbonsor natural gases and oxygen may be oxidized together at a hightemperature, in the range of 1200 to 1600 C., to form hydrogen andcarbon monoxide, and in such a process, it is desirable to have thevoxidation products discharged from the high temperature zone as quicklyas possible. In this ellipsoidal furnace, the high temperature zone isrelatively small and is concentrated around the foci where the heatgenerating means are positioned. Thus, by charging reactants throughthese relatively concentrated zones, at high controlled velocities, itis possible to obtain contacts for only a small fractional part of asecond. In this particular process and at the temperature rangespecified, it would be necessary to employ refractory types of liner forthe combustion chamber. However, it may be noted that a liner providingonly a 10% reflecting power from one focus point to the other, wouldproduce a substantial temperature increase within the zones of the foci,where high temperatures are employed, of the order of 200 F. and upward.

An ellipsoidal shaped furnace may also be constructed to withstand highpressure conditions far easier than the conventional rectangular orboxed shape furnaces. The furnace housing may be designed in the mannerof a pressure vessel, to withstand pressures of several hundred poundsper square inch and at the same time be of relatively lightconstruction.

Another advantage found in this improved furnace construction, wherefuel burners are employed, is that carbon formation will be minimized.The increased temperature at each of the heat sources, where gas burnersand the like are used, will tend to bring about more complete combustionof the products to carbon monoxide.

Conventional types of furnaces or heaters do not usually obtain hightemperature zones by means of reflected heat, but more generally dependon direct radiation from their heat generating sources bodies.Conventional type heaters, also, are not usually constructed in a shapewhich makes them suitable for maintaining superatrnospheric pressurestherein.

One embodiment of the improved 'furnace of this invention comprises aninsulated furnacel housing, an internal combustion chamber having a trueellipsoidal shape, fuel burners or other heat generating means producingheat at the foci of said ellipsoidal shaped combustion chamber, inletsto said chamber which are arranged to discharge reactants to the hightemperature `zones at each of the foci, and combustion product outletsfrom said chamber. The outlets from the combustion chamber arepreferably positioned equidistantly from each of the high temperaturezones, in other words, the outlets are centrally located around theperiphery of the chamber in a plane perpendicular to and bisecting aline joining the foci. Also, in a preferable embodiment of the heater,the internal surface of the combustion chamber is made as smooth aspossible and is of a material that provides a substantially high degreeof reilectivity.

The construction of the improved ellipsoidai furnace, as well asadditional advantages, will be made more apparent upon reference to theaccompanying-drawings and the following description thereof.

. Figure l of the drawing is a sectional elevational view through oneform of the ellipsoidal type of furnace.

Figure 2 ci the drawing is a sectional view of a somewhat different formof the .ellsoidal type of furnace.

In Figure l of the drawing the shell I of the combustion chamber isshown to be ellipsoidal in shapeA and is covered with an insulatingmaterial 2. The insulating material 2 may be of any of the commonly usedtypes such as mineral wool, magnesia block, asbestos, or variousmixtures of insulating cements and the like. Inlet pipes 3 pass throughthe ends of the ellipsoid into the` combustion Zone and connect withburners 4. The burners are placed such that the flames produced areopposed to each other and concentrated at the geometrical foci 5 of theellipsoidal shaped combustion chamber i. By thus concentrating the namesat each of the foci, reflected heat will tend to increase the heatintensity at each of the two zones of the focus points Y'.i. Outletports or 2conduits are spaced around the periphery of chamber l, in aplane perpendicularly .bisecting a line joining the foci `of theellipsoidal shaped chamber I. The outlet ports serve to dischargecombustion products from the chamber to suitable receiving apparatus. Inthis particular form of the heater, the reactant and the combustiblematerials are charged together through each of the lines 3, thus the.reactant materials are contacted in the high temperature zone of the'flames and of the refiected heat, for a short period of contact timeonly, prior to being discharged from .the combustion zone by way of orindirectly from radiatingv conduit 6. It may be noted, that bypositioning the outlet conduits E in a plane which perpendicularlybisects a line joining the foci of the chamber, that each of the outletsare positioned equidistantly from the foci 5 or high temperature zonesof the furnace.

In Figure 2 of the drawing a slightly diiferent form of the ellipsoidalheater is shown wherein an ellipsoidal combustion chamber is formedwithin a furnace housing 1, which may in turn be of a solid heatresisting material such as porcelain, Carborundum or of arefractory-like material. At the foci 8 of the ellipsoidal chamber, heatsources are provided by means of electric arcs between electrodes 9. Theelectrodes 9 are served by electric power lines lo and Il, and arepositioned such that the arc produced between the electrodes will passthrough the focus points 8. Inlet conduits I2 pass through the housing'i and terminate just short of the foci 8 so that reactant materials maybe discharged directly to the high temperature genes, Outlet conduitsi3, like those of Figure 1, are positioned around the periphery of theellipsoidal combusftion Zone, so that they are each equally spaced fromthe high temperature Vzones at the foci 8, and the Products ofcombustion are thereby subjected to equal periods of contact and equaltemperature conditions.

In this second form of heater or furnace, illustrated in Figure 2, Veryconcentrated high temperature Vzones may be obtained by means 0f theelectric arcs and by means of reflected hea-t energy from one to theother, such that very short time contacts may be obtained in therelatively concentrated zones for materials discharged theretc. As haspreviously been noted, short contact times are particularly desirable inmany hydrocarbon .oxidation or combustion processes and thatsuperatmospheric pressure operation at increased temperatures may alsobe very desirable.

It is obvious that other and additional modifications thanthose shownmay be made in the ellipsoidal type of heater. The ellipsoidalcombustion Zone need not always be horizontally positioned, asillustrated, for it may be mounted angularly or vertically, with theopposing heat sources vertically aligned one above the other. Thepositioning of the inlet and outlet conduits may be modied, other typesof burners or heat generating means may be employed, and many types ofmaterials which have not been specically mentioned, may be used for thecombustion chamber or for heat insulating purposes. However, suchmodifications and substitutions are held to be within the broad scope ofthis invention.

I claim as my invention:

l, A furnace of the class described comprising an ellipsoidal shapedcombustion chamber, means for maintaining an independent heat source ateach of the foci of said ellipsoidal chamber, a pair of inlet conduitsto said chamber, each of said conduits being arranged and positioned toterminate at a point adjacent one .of said heat sources whereby reactantmaterials are passed through said heat sources and said foci, outletsfrom said combustion chamber, each of said outlets being spacedequidistant between said foci, arid discharge conduits connecting withsaid out- 2. A furnace of the class described comprising a pressuretight ellipsoidal shaped combustion chamber, vmeans for maintaining anindependent heat source at each of the foci of said ellipsoidal chamber,a pair of inlet conduits to said chamber', each of said conduits beingarranged and positioned to terminate at a point adjacent one of saidheat sources whereby reactant materials are passed through said heatsources and said foci, outlets from said combustion chamber, each ofsaid outlets being spaced equidistant between said foci, and dischargeconduits connecting with said outlets.

3. A furnace of the class described comprising a furnace housing, anellipsoidal shaped combustion chamber, burners positioned within saidchamber, said burners being arranged to provide opposing heat sources atthe geometrical foci of said ellipsoidal combustion chamber, inletconduits connecting with said burners, a plurality of outlets from saidcomposite chamber, said outlets being spaced around the periphery ofsaid combustion chamber in a plane which perpendicularly bisects a linejoining the foci and discharge conduits connecting with said outlets.

4. A furnace of the class described comprising a furnace housing, apressure tight ellipsoidal shaped combustion chamber, burners positionedwithin said chamber, said burners being arranged to provide opposingheat sources at the geometrical foci of said ellipsoidal combustionchamber, inlet conduits connecting with said burners, a plurality ofoutlets from said composite chamber,

3 said outlets being spaced around the periphery of said combustionchamber in a plane which perpendicularly bisects a line joining the fociand discharge conduits connecting with said outlets.

5. The furnace of claim 1 further characterized in that said heatsources are provided by electric arcs located at the foci of saidchamber.

6. A furnace of the class described comprising an ellipsoidal shapedcombustion chamber, means for maintaining an independent heat source ateach of the geometrical foci of said ellipsoidal chamber, means forintroducing iiuid to said chamber at points adjacent said foci, andspaced outlet ports at the periphery of the chamber in a planeperpendicularly bisecting a line joining said foci.

CHARLES H. WATKINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 991,404 Woodworth May 2, 19111,232,362 Miner July 3, 1917 FOREIGN PATENTS Number Country Date 122,395Great Britain Sept. 19, 1918 510,193 France Nov. 29, 1920 559,709 GreatBritain Mar. 2, 1944

